PHP'nizin SHA1 şifreleme fonksiyonunu tanımadığı durumlar olabilir. Bu oluşabilecek sorunların önüne geçebilmek için aşağıdaki kodu şifreleme yapacağınız sayfaya ekleyin.

if (!function_exists('sha1'))
{
	function sha1($str)
	{
		// If we have mhash loaded in, use it instead!
		if (function_exists('mhash') && defined('MHASH_SHA1'))
			return bin2hex(mhash(MHASH_SHA1, $str));

		$nblk = (strlen($str) + 8 >> 6) + 1;
		$blks = array_pad(array(), $nblk * 16, 0);

		for ($i = 0; $i < strlen($str); $i++)
			$blks[$i >> 2] |= ord($str{$i}) << (24 - ($i % 4) * 8);

		$blks[$i >> 2] |= 0x80 << (24 - ($i % 4) * 8);

		return sha1_core($blks, strlen($str) * 8);
	}

	// This is the core SHA-1 calculation routine, used by sha1().
	function sha1_core($x, $len)
	{
		@$x[$len >> 5] |= 0x80 << (24 - $len % 32);
		$x[(($len + 64 >> 9) << 4) + 15] = $len;

		$w = array();
		$a = 1732584193;
		$b = -271733879;
		$c = -1732584194;
		$d = 271733878;
		$e = -1009589776;

		for ($i = 0, $n = count($x); $i < $n; $i += 16)
		{
			$olda = $a;
			$oldb = $b;
			$oldc = $c;
			$oldd = $d;
			$olde = $e;

			for ($j = 0; $j < 80; $j++)
			{
				if ($j < 16)
					$w[$j] = @$x[$i + $j];
				else
					$w[$j] = sha1_rol($w[$j - 3] ^ $w[$j - 8] ^ $w[$j - 14] ^ $w[$j - 16], 1);

				$t = sha1_rol($a, 5) + sha1_ft($j, $b, $c, $d) + $e + $w[$j] + sha1_kt($j);
				$e = $d;
				$d = $c;
				$c = sha1_rol($b, 30);
				$b = $a;
				$a = $t;
			}

			$a += $olda;
			$b += $oldb;
			$c += $oldc;
			$d += $oldd;
			$e += $olde;
		}

		return dechex($a) . dechex($b) . dechex($c) . dechex($d) . dechex($e);
	}

	function sha1_ft($t, $b, $c, $d)
	{
		if ($t < 20)
			return ($b & $c) | ((~$b) & $d);
		if ($t < 40)
			return $b ^ $c ^ $d;
		if ($t < 60)
			return ($b & $c) | ($b & $d) | ($c & $d);

		return $b ^ $c ^ $d;
	}

	function sha1_kt($t)
	{
		return $t < 20 ? 1518500249 : ($t < 40 ? 1859775393 : ($t < 60 ? -1894007588 : -899497514));
	}

	function sha1_rol($num, $cnt)
	{
		$z = hexdec(80000000);
		if ($z & $num)
			$a = ($num >> 1 & (~$z | 0x40000000)) >> (31 - $cnt);
		else
			$a = $num >> (32 - $cnt);

		return ($num << $cnt) | $a;
	}
}

Kod SMF'den alınmadır...